The United States has 22 Air Route Traffic Control Centers (ARTCC). They are operated by and are part of the Federal Aviation Administration of the U.S. Department of Transportation. An ARTCC controls aircraft flying in a specified region of airspace, known as a flight information region (FIR), typically during the en route portion of flight. The purpose of control is to promote the safe, orderly, and expeditious flow of air traffic and prevent collisions. In countries other than the U.S., such a facility is generally known as an area control center.Albuquerque Air Route Traffic Control CenterAnchorage Air Route Traffic Control CenterAtlanta Air Route Traffic Control CenterBoston Air Route Traffic Control CenterChicago Air Route Traffic Control CenterCleveland Air Route Traffic Control CenterDenver Air Route Traffic Control CenterFort Worth Air Route Traffic Control CenterHonolulu Air Route Traffic Control CenterHouston Air Route Traffic Control CenterIndianapolis Air Route Traffic Control CenterJacksonville Air Route Traffic Control CenterKansas City Air Route Traffic Control CenterLos Angeles Air Route Traffic Control CenterMemphis Air Route Traffic Control CenterMiami Air Route Traffic Control CenterMinneapolis Air Route Traffic Control CenterNew York Air Route Traffic Control CenterOakland Air Route Traffic Control CenterSalt Lake City Air Route Traffic Control CenterSeattle Air Route Traffic Control CenterWashington Air Route Traffic Control Center